Personally I prefer to not have it become such a huge thing. It's fast-response box after all.
However, the ability to inline add attachments, where it slides down, showing clearly it's part of the response. I like that. As are some of the moderator quick-inline-mod-options .. very handy, it's a click-click experience atm, I could do with less clicks.

This is the reason why "Polloption" is on the right side. If you have no chance to create a poll it is easy to let the place empty. The NG-editor isn't (only) an alternative for the inline editor, it should be exchange the "normal editor" in every place.

What I personally see can happen here with this idea is the need to change to another page to change options is taken away. Unnecessary page loads are actually "user enemy number one", aren't they? And if the suggestion is added, it doesn't interfere with quick responses either. So no loss there really Floris. You can continue to answer quickly, but if you do decide to watch the thread or want to recieve emails, because you have these options turned off, then those options are there too to easily select, without the new page having to load.

As for the addition of a thread, obviously doing this action requires a new page load every time anyway, as you only have a button to press to start the action. As a thread starting editor, this idea might be too simplistic. (Is that possible?) It does make for a very clean interface, which the current solution isn't quite, because it causes the user to scroll down and search or scan for the needed auxiliary function. If the editor has expanded down the page, then the user will have to scroll down, scan and then click/ activate what she needs. So in essence, in many cases, this improvement would not detract the usability by adding more user action. It would be a one to one trade-off. It would be a scroll or two down the page and scan for function for one click to open the needed function and I think the orderliness of the "NG-Editor" suggestion wins over as reasoning why it could (or should) be done. At least it does for me.

Also the smilie improvement alone is worth implementing the suggestion, because a lot of forum owners add a lot of smilies. The drop down slider is a great way to show them off and make them available for selection in the post, if and when they are needed. If they aren't needed, then they are out of sight and not making the user crazy with all the animations. This solution is also better than the pull down in the menu at the top, because if there are more than say 20 smilies, the overlay starts to hide the text and with adding more than one smilie to the text, it is almost a PITA, because the overlay with the smilie closes again after the selection and I have to reclick it open to add the next smilie and we want to avoid PITAs right?